平坦的

The river slows on the flat bottom.

河水在的河床减慢了流速。

The rim is flat and there is a rather deep well, or cavetto.

边缘的，有一个相当深的底部，或称为圆底。

Various vehicles bowl along over the smooth highway.

各种车辆在的高速公路疾驶。

Heading away from the mountains, I soon found an easier path leading downhill to the village.

我背着山走了不久, 就发现了一条通往该村比较的下山路。